In the past, scanning of large original drawings or the like, and of documents and pictures at high resolutions for computer storage and processing purposes has been accomplished by rotating drum multipass scanners or lately by scanners containing multiple modular sensors.
The prior equipment has been deficient in that it is extremely expensive, often complicated and difficult to operate. Further, the equipment of the past has often lacked the ability to maintain its accuracy of scanning, especially if moved, and thus required expensive skilled technicians on-site for re-adjustment. Prior equipment having multiple modular sensors often has suffered from distortion of the scanned image due to mechanical misalignment of the multiple modular sensors, giving overlap between adjacent sensors leading to doubling of pixels in the scanned image, or giving separation between adjacent pixel sensors leading to missed pixels in the scanned image.
It is the object of the invention to devise a method and an apparatus by which it is possible to align line segments, separately or in a matrix built image, the individual line segments being collected by a number of sensor arrays.
The object is obtained in that each sensor array has a total visual field which is divided into an active visual field and a visual field edge where aligning means present in a visual field falling within two sensor arrays is depicted by initialization in at least one element in a segment vector, whereafter the active visual fields of the sensor arrays are determined in dependence on the position of the aligning means in the segment vectors, and where the lines are aligned by the cells of the segment vectors representing the active visual field, whereas the cells representing the visual field edge are skipped.
The method is carried out by means of an apparatus being characterized in that two adjacent sensor arrays have partly coinciding visual fields, that aligning means are provided at such place in an area between the object plane and the sensor arrays where the visual fields of the latter coincide, that means are provided for determining the pixel position of the aligning means in the segment vectors, and that means are provided for multiplexing the segment vectors so as to become aligned to form a line vector, the pixel of which represent the entire line, the alignment being adapted for skipping the pixels of the segment vectors between the extreme point of the individual segment vectors and the pixel position of the aligning means.
By positioning the aligning means in the said area it will not form part of the image collected during the sensing, as it is imaged in the visual field edge which is skipped during the sensing.
It is possible to carry out the invention with stationary sensor arrays which e.g. by means of line CCD-sensors scan intelligence on an original while the latter is driven past the sensor arrays. It is also possible to scan intelligence on a stationary original while the sensor arrays are driven past the original. Finally, the original may be stationary in relation to the sensor arrays which may then be composed by a number of CCD-cameras, the aggregate visional field of which substantially corresponds to the area of the original.